JP7426323B2 - Reactor - Google Patents

Description

TECHNICAL FIELD This disclosure relates to nuclear reactors.

For example, Patent Documents 1 and 2 disclose a structure in which fuel in a reactor core is formed in a disk-shaped layer.

Japanese Unexamined Patent Publication No. 17689/1989 Japanese Patent Application Publication No. 5-45485

In a nuclear reactor, it is necessary to retain fission products (FP) released by fission of nuclear fuel material inside the reactor vessel, and to efficiently extract heat from the core of the reactor, which is made up of nuclear fuel material. is desired.

The present disclosure solves the above-mentioned problems, and aims to provide a nuclear reactor that can efficiently extract heat from a reactor core while retaining nuclear fission products inside a reactor vessel.

In order to achieve the above object, a nuclear reactor according to one aspect of the present disclosure includes a fuel part in which a coating part is provided on the surface of nuclear fuel material, and a heat conduction part.

The present disclosure can efficiently extract heat from a reactor core while preserving fission products.

FIG. 1 is a schematic diagram of a nuclear power generation system using a nuclear reactor according to an embodiment. FIG. 2 is a schematic diagram showing a nuclear reactor according to the first embodiment. FIG. 3 is a schematic cross-sectional view of the nuclear reactor according to the first embodiment. FIG. 4 is a schematic cross-sectional view of another example of the nuclear reactor according to the first embodiment. FIG. 5 is a partially cut-out enlarged schematic diagram of the nuclear reactor according to the first embodiment. FIG. 6 is a partially cut-out enlarged schematic diagram of the nuclear reactor according to the first embodiment. FIG. 7 is a partially cut-out enlarged schematic diagram of the nuclear reactor according to the first embodiment. FIG. 8 is a partially cut-out enlarged schematic diagram of the nuclear reactor according to the first embodiment. FIG. 9 is a schematic cross-sectional view of the fuel section of the nuclear reactor according to the first embodiment. FIG. 10 is a schematic perspective view of the fuel section of the nuclear reactor according to the first embodiment. FIG. 11 is a schematic perspective view of another example of the fuel section of the nuclear reactor according to the first embodiment. FIG. 12 is a schematic perspective view of another example of the fuel section of the nuclear reactor according to the first embodiment. FIG. 13 is a schematic cross-sectional view of another example of the nuclear fuel of the nuclear reactor according to the first embodiment. FIG. 14 is a schematic perspective view of another example of the fuel section of the nuclear reactor according to the first embodiment. FIG. 15 is a schematic diagram showing a nuclear reactor according to the second embodiment. FIG. 16 is a schematic cross-sectional view of a nuclear reactor according to Embodiment 2. FIG. 17 is a schematic diagram showing another form of the nuclear reactor according to the second embodiment. FIG. 18 is an enlarged schematic diagram of the heat conduction section of the nuclear reactor according to the second embodiment. FIG. 19 is a schematic diagram showing another form of the nuclear reactor according to the second embodiment. FIG. 20 is an explanatory diagram of the form shown in FIG. 18. FIG. 21 is a schematic diagram showing a nuclear reactor according to Embodiment 3.

Embodiments according to the present disclosure will be described in detail below based on the drawings. Note that the present invention is not limited to this embodiment. Furthermore, the constituent elements in the embodiments described below include those that can be easily replaced by those skilled in the art, or those that are substantially the same.

FIG. 1 is a schematic diagram of a nuclear power generation system using a nuclear reactor according to an embodiment. As shown in FIG. 1, the nuclear power generation system 50 includes a reactor vessel 51, a heat exchanger 52, a heat conduction section 53, a refrigerant circulation means 54, a turbine 55, a generator 56, and a cooler 57. , and a compressor 58.

The reactor vessel 51 has a nuclear reactor 11 (12, 13) of an embodiment described later. The reactor vessel 51 houses the nuclear reactor 11 (12, 13) therein. The reactor vessel 51 stores the nuclear reactor 11 (12, 13) in a sealed state. The reactor vessel 51 is provided with an opening/closing part, such as a lid, so that the reactor 11 (12, 13) placed therein can be stored or taken out. The reactor vessel 51 can maintain a sealed state even when a nuclear fission reaction occurs in the reactor 11 (12, 13) and the inside becomes high temperature and pressure. The reactor vessel 51 is formed of a material that has neutron beam shielding performance.

The heat exchanger 52 exchanges heat with the nuclear reactor 11 (12, 13). The heat exchanger 52 of the embodiment recovers the heat of the nuclear reactor 11 (12, 13) via the solid high heat conductive material of the heat conductive part 53 that is partially disposed inside the reactor vessel 51. In addition, the heat conduction part 53 shown in FIG. 1 is a general term for the heat conduction parts 3, 103, and 104 mentioned later, and is schematically shown.

The refrigerant circulation means 54 is a path for circulating refrigerant, and is connected to the heat exchanger 52, the turbine 55, the cooler 57, and the compressor 58. The refrigerant flowing through the refrigerant circulation means 54 flows through the heat exchanger 52 , the turbine 55 , the cooler 57 , and the compressor 58 in this order, and the refrigerant that has passed through the compressor 58 is supplied to the heat exchanger 52 . Therefore, the heat exchanger 52 performs heat exchange between the solid high heat conductive material of the heat conductive portion 53 and the refrigerant flowing through the refrigerant circulation means 54 .

The refrigerant that has passed through the heat exchanger 52 flows into the turbine 55 . The turbine 55 is rotated by the energy of the heated refrigerant. In other words, the turbine 55 converts the energy of the refrigerant into rotational energy and absorbs energy from the refrigerant.

The generator 56 is connected to the turbine 55 and rotates together with the turbine 55. The generator 56 generates electricity by rotating with the turbine 55.

The cooler 57 cools the refrigerant that has passed through the turbine 55. The cooler 57 is a chiller or a condenser when temporarily liquefying the refrigerant.

The compressor 58 is a pump that pressurizes the refrigerant.

The nuclear power generation system 50 transmits heat generated by the reaction of nuclear fuel in the nuclear reactor 11 (12, 13) to the heat exchanger 52 through the heat conduction section 53. In the nuclear power generation system 50 , in the heat exchanger 52 , the refrigerant flowing through the refrigerant circulation means 54 is heated by the heat of the highly thermally conductive material of the heat conductive part 53 . That is, the refrigerant absorbs heat in the heat exchanger 52. Thereby, the heat generated in the nuclear reactor 11 (12, 13) is recovered by the refrigerant. After being compressed by the compressor 58, the refrigerant is heated as it passes through the heat exchanger 52, and the compressed and heated energy rotates the turbine 55. The refrigerant is then cooled down to a reference state in the cooler 57 and supplied to the compressor 58 again.

As described above, the nuclear power generation system 50 transfers the heat extracted from the nuclear reactor 11 (12, 13) to the refrigerant, which is the medium that rotates the turbine 55, through the highly thermally conductive material. Thereby, the nuclear reactor 11 (12, 13) and the refrigerant that is the medium that rotates the turbine 55 can be isolated, and the possibility that the medium that rotates the turbine 55 will be contaminated can be reduced.

[Embodiment 1]
FIG. 2 is a schematic diagram showing a nuclear reactor according to the first embodiment. FIG. 3 is a schematic cross-sectional view of the nuclear reactor according to the first embodiment. FIG. 4 is a schematic cross-sectional view of another example of the nuclear reactor according to the first embodiment. FIG. 5 is a partially cut-out enlarged schematic diagram of the nuclear reactor according to the first embodiment. FIG. 6 is a partially cut-out enlarged schematic diagram of the nuclear reactor according to the first embodiment. FIG. 7 is a partially cut-out enlarged schematic diagram of the nuclear reactor according to the first embodiment. FIG. 8 is a partially cut-out enlarged schematic diagram of the nuclear reactor according to the first embodiment. FIG. 9 is a schematic cross-sectional view of the fuel section of the nuclear reactor according to the first embodiment. FIG. 10 is a schematic perspective view of the fuel section of the nuclear reactor according to the first embodiment. FIG. 11 is a schematic perspective view of another example of the fuel section of the nuclear reactor according to the first embodiment. FIG. 12 is a schematic perspective view of another example of the fuel section of the nuclear reactor according to the first embodiment. FIG. 13 is a schematic cross-sectional view of another example of the nuclear fuel of the nuclear reactor according to the first embodiment. FIG. 14 is a schematic perspective view of another example of the fuel section of the nuclear reactor according to the first embodiment.

As shown in FIGS. 2 to 5, the nuclear reactor 11 includes a fuel part (core) 1, a shield part 2, a heat conduction part 3, and a control mechanism 4.

The fuel part 1 has a fuel layer 1A formed in a plate shape. In the first embodiment, the fuel layer 1A is formed into a disk shape. A plurality of fuel layers 1A are provided and arranged side by side so that their plate surfaces face each other. The direction in which the plurality of fuel layers 1A are lined up with their plate surfaces facing each other is sometimes referred to as the axial direction. The fuel layer 1A contains uranium, which is a nuclear fuel material.

The shielding part 2 covers the periphery of the fuel part 1. The shielding part 2 is made of, for example, a metal block, and prevents the radiation from leaking to the outside that covers the fuel part 1 by reflecting the radiation (neutrons) irradiated from the nuclear fuel. The shielding part 2 may be called a reflector depending on the neutron scattering and neutron absorption capabilities of the material used. The shielding part 2 has a shielding layer 2A. The shielding layer 2A is formed in a plate shape to cover the periphery of the fuel layer 1A along the outer peripheral surface 1Aa of the fuel layer 1A. The shielding layer 2A has a through hole 2Aa penetrating both plate surfaces and is formed in an annular shape (ring shape). In the shielding part 2, the fuel layer 1A is accommodated in the through hole 2Aa.

The shielding part 2 has a lid part 2B formed in a plate shape so as to cover the fuel part 1 provided at both ends in the axial direction. The shielding part 2 accommodates the fuel part 1 in a sealed interior with each shielding layer 2A and each lid part 2B. When housing the fuel part 1 inside, it is preferable to fill the inside of the sealed structure with an inert gas such as nitriding gas, for the purpose of preventing oxidation of the inside.

The heat conduction part 3 has a heat conduction layer 3A formed in a plate shape. The thermally conductive layer 3A is stacked in the axial direction so that its plate surface contacts the plate surface of the fuel layer 1A. The heat conductive layer 3A is formed to have a larger outer diameter than the fuel layer 1A and the shielding layer 2A, and protrudes to the outer periphery of the fuel layer 1A and the shielding layer 2A. The thermally conductive layer 3A of the first embodiment is formed in a disk shape and is provided so as to protrude in the radial direction from the entire outer periphery of the fuel layer 1A and the shielding layer 2A. The radial direction is a direction perpendicular to the stacking direction (axial direction). The thermally conductive layers 3A are alternately stacked with the fuel layers 1A of the fuel section 1 in the axial direction, and are provided so as to extend from the inside of the sealed shielding section 2 to the outside. Further, the heat conductive layer 3A transmits heat generated by the fission reaction of the nuclear fuel in the fuel layer 1A to the outside of the shield layer 2A by solid heat conduction. For example, titanium, nickel, copper, or graphite can be used for the thermally conductive layer 3A. In particular, graphene can be used as graphite. Graphene has a structure in which a hexagonal lattice made of carbon atoms and their bonds is continuous, and heat transfer efficiency can be improved by setting the direction of continuous hexagonal lattice as the direction of heat transfer. The heat conductive layer 3A is provided so that a portion extending to the outside of the shielding layer 2A can exchange heat with the refrigerant inside the reactor vessel 51.

The control mechanism 4 is disposed on the shielding portion 2 on the outside of the fuel layer 1A in the radial direction. The control mechanism 4 of the first embodiment is configured as a control drum 4A, as shown in FIG. The control drum 4A has a cylindrical shape, and is formed in a so-called drum shape. The control drum 4A has a cylindrical shape extending in the axial direction of the nuclear reactor 11. The control drum 4A is provided so as to penetrate the shielding part 2 and the heat conducting part 3 in the axial direction. A plurality of control drums 4A (12 in the first embodiment) are evenly arranged in the circumferential direction around the axial direction of the nuclear reactor 11. The control drum 4A is rotatably provided around a cylinder. The control drum 4A is provided with a neutron absorber 4Aa on a part of the outer periphery of the cylinder. The neutron absorber 4Aa is provided at a position facing at least the outer circumferential surface 1Aa of the fuel layer 1A, and may be made of boron carbide (B ₄ C), for example. The neutron absorber 4Aa rotates as the control drum 4A rotates, approaching or separating from the outer circumferential surface 1Aa of the fuel section 1, which is the reactor core. When the neutron absorber 4Aa approaches the fuel section 1, the reactivity of the fuel section 1 decreases, and when the neutron absorber 4Aa moves away from the fuel section 1, the reactivity of the fuel section 1 increases. In this way, the control drum 4A can control the reactivity of the fuel section 1, which is the reactor core, by rotating the neutron absorber 4Aa toward or away from the fuel section 1, and can control the core temperature of the fuel section 1. . The core temperature is the average core temperature extracted to the outside of the shielding part 2 by the heat conduction part 3. The control drum 4A has a drive section (not shown) that drives its rotation. The drive section is biased to rotate so that the neutron absorber 4Aa of the control drum 4A approaches the inner surface of the fuel section 1, and automatically rotates when the connection with the control drum 4A is severed by a clutch mechanism or the like. Specifically, the neutron absorber 4Aa is configured to approach the outer circumferential surface 1Aa of the fuel section 1. Therefore, for example, in an emergency when the temperature of the fuel section 1 exceeds a set temperature, the neutron absorber 4Aa can automatically approach the inner surface of the fuel section 1 to reduce the reactivity of the fuel section 1. can.

Note that the control mechanism 4 is not limited to the control drum 4A, but may be a control rod 4B as shown in FIG. 4. A plurality of control rods 4B are provided to penetrate the fuel part 1 and the heat conduction part 3 in the axial direction. The control rod 4B is formed into a rod shape. The control rod 4B is formed to extend in the axial direction of the nuclear reactor 11. The control rod 4B is provided to be slidable in the axial direction. The control rod 4B is formed of a neutron absorber. For example, boron carbide (B ₄ C) can be used as the neutron absorber. The control rods 4B move in the axial direction by sliding and are inserted into the cylindrical interior of the fuel section 1 or pulled out to the cylindrical outside of the fuel section 1, thereby approaching the fuel section 1 that is the reactor core. Or it is provided so that it can be separated. When the control rod 4B is inserted into the fuel section 1, the reactivity of the fuel section 1 decreases, and when the control rod 4B is withdrawn from the fuel section 1, the reactivity of the fuel section 1 increases. In this way, the control rod 4B can control the reactivity of the fuel part 1, which is the reactor core, by sliding the neutron absorber into or out of the fuel part 1, and can control the core temperature of the fuel part 1. The control rod 4B has a drive section (not shown) that drives the slide. The drive section has a slide biased so that the control rod 4B is inserted into the inner surface of the fuel section 1, and when the connection with the control rod 4B is severed by a clutch mechanism or the like, the control rod is automatically inserted. 4B into the fuel part 1. Therefore, for example, in an emergency when the temperature of the fuel section 1 exceeds a set temperature, the control rod 4B can be automatically inserted into the fuel section 1 to lower the reactivity of the fuel section 1.

Therefore, in the nuclear reactor 11 of the first embodiment, the heat generated by the fission reaction of the nuclear fuel in the fuel section 1 can be extracted to the outside of the shielding section 2 by solid heat conduction using the heat conducting section 3 . The heat extracted to the outside of the shielding part 2 is transferred to the refrigerant, causing the turbine 55 to rotate.

In the nuclear reactor 11 of the first embodiment, the heat of the nuclear fuel in the fuel part 1 can be extracted to the outside of the shield part 2 by solid heat conduction through the heat conduction part 3 (see arrow in FIG. 2), and the heat can be transferred to the refrigerant. As a result, the nuclear reactor 11 of the first embodiment can prevent leakage of radioactive substances and the like. In addition, in the nuclear reactor 11 of Embodiment 1, since the heat conduction part 3 is arranged to extend to the inside of the fuel part 1 and the outside of the shielding part 2, compared to the case where there is no heat conduction part 3 inside, the It is possible to take out the heat of the nuclear fuel in the portion 1 to the outside of the shielding portion 2 while suppressing the heat transfer distance. As a result, the nuclear reactor 11 of the first embodiment can ensure a high output temperature. Although the nuclear reactor 11 of Embodiment 1 has been described in which the heat conduction section 3 is configured to take out heat by solid heat conduction, for example, as another heat conduction section, a fluid heat conduction section using a heat pipe in which a fluid is sealed is used. It is also possible to use a form that extracts heat.

In addition, in the nuclear reactor 11 of the first embodiment, the fuel layer 1A of the fuel section 1 and the heat conductive layer 3A of the heat conductive section 3 are formed in plate shapes and arranged alternately overlapping each other with their plate surfaces facing each other. The heat conductive layer 3</b>A is arranged such that its plate-shaped outer peripheral portion extends outside the shielding portion 2 . Therefore, in the nuclear reactor 11 of Embodiment 1, the heat conduction part 3 can be arranged so as to penetrate the shield part 2 and extend to the inside of the fuel part 1 and the outside of the shield part 2. The heat of the portion 1 can be taken out to the outside of the shielding portion 2 by solid heat conduction. Note that the thickness of the plurality of plate shapes of the fuel layer 1A and the plurality of plate shapes of the heat conductive layer 3A may be changed. Moreover, by covering the outside of the shielding part 2 from which the heat conduction part 3 does not extend with a heat insulating material, the efficiency of heat recovery by the heat conduction part 3 can be improved.

In addition, in the nuclear reactor 11 of the first embodiment, as shown in FIG. 6, the heat conduction section 3 has a plurality of cuts 3B formed in the portion of each heat conduction layer 3A that extends to the outside of the shielding section 2. Good. The cuts 3</b>B are formed to extend in the radial direction away from the outer surface of the shielding part 2 , and are formed in plural lines on the outer periphery of the heat conductive part 3 along the outer periphery of the shielding part 2 . That is, the heat conduction part 3 is a part extending to the outside of the shielding part 2, and has a cut in the part that exchanges heat with the refrigerant circulating in the refrigerant circulation means 54 in order to perform heat exchange in the heat exchanger 52. 3B forms a gap through which the refrigerant passes. Therefore, the nuclear reactor 11 of the first embodiment can improve the efficiency of transmitting the heat extracted by the heat conduction section 3 to the refrigerant.

In the heat conduction part 3 formed to extend in the radial direction away from the outer surface of the shielding part 2, the heat extracted is high on the radial inside near the fuel part 1 and low on the radial outside far from the fuel part 1. For example, in FIG. 6, when the heat conduction part 3 formed to extend in the radial direction away from the outer surface of the shielding part 2 is divided into two regions in the radial direction by an imaginary line L, the diameter is smaller than the imaginary line L. The temperature of the extracted heat is higher on the inside in the radial direction than on the outside in the radial direction. Therefore, when performing heat exchange with the refrigerant in the heat conduction section 3, the refrigerant is first passed radially outward from the imaginary line L, and then returned to pass radially inward from the imaginary line L. , delivers the refrigerant to the heat exchanger 52. In this way, the efficiency of transmitting the heat taken out by the heat conduction section 3 to the refrigerant can be increased.

In addition, in the nuclear reactor 11 of the first embodiment, as shown in FIG. 7, the heat transfer section 3 includes a heat transfer tube 3C through which a refrigerant flows in a portion of each heat transfer layer 3A extending outside the shielding section 2. It is good if it is penetrated. A plurality of heat exchanger tubes 3</b>C are formed along the outer periphery of the heat conductive part 3 so as to extend along the outer periphery of the shielding part 2 . That is, the heat conduction part 3 is a part extending to the outside of the shielding part 2, in which the refrigerant is exchanged with the refrigerant circulating in the refrigerant circulation means 54 in order to perform heat exchange in the heat exchanger 52. The circulating heat exchanger tube 3C is penetrated. Therefore, the nuclear reactor 11 of the first embodiment transfers the heat extracted by the heat transfer section 3 to the refrigerant via the heat transfer tube 3C. In addition, the nuclear reactor 11 of the first embodiment indirectly transfers the heat extracted by the heat conduction section 3 to the refrigerant through the heat transfer tube 3C, so that radiation shielding performance can be maintained.

For example, in FIG. 7, when the heat conduction part 3 that is formed to extend in the radial direction away from the outer surface of the shielding part 2 is divided into two regions in the radial direction by an imaginary line L, the diameter is smaller than that of the imaginary line L. The temperature of the extracted heat is higher on the inside in the radial direction than on the outside in the radial direction. Therefore, a plurality of heat exchanger tubes 3C are arranged in the radial direction, with an inner heat exchanger tube 3Ca disposed radially inward from the imaginary line L, and an outer heat exchanger tube 3Cb disposed radially outward from the imaginary line L. including. When performing heat exchange with the refrigerant in the heat conduction section 3, the refrigerant is first passed through the outer heat exchanger tube 3Cb, then returned and passed through the inner heat exchanger tube 3Ca, and then sent out to the heat exchanger 52. . In this way, the efficiency of transmitting the heat taken out by the heat conduction section 3 to the refrigerant can be increased.

In addition, in the nuclear reactor 11 of the first embodiment, as shown in FIG. Preferably, it is formed into a plate shape. For example, graphene can be used for the heat conduction part 3. Graphene has a structure in which a hexagonal lattice made of carbon atoms and their bonds is continuous, and has high heat conductivity in the continuous direction of the hexagonal lattice. . By using this graphene as the sheet-like plate material 3D, the hexagonal lattice is continuous along the surface of the plate material 3D. Then, the plate materials 3D are stacked in the axial direction to form a plate shape. Then, the heat conduction part 3 has high heat transferability in the radial direction along the surface of the plate material 3D. Therefore, the thermally conductive portion 3 has high heat transferability to the portion extending in the radial direction to the outside of the shielding portion 2. As a result, the nuclear reactor 11 of the first embodiment can improve the efficiency of transmitting the heat extracted by the heat conduction section 3 to the refrigerant.

Further, in the nuclear reactor 11 of the first embodiment, as shown in FIG. 9, the fuel layer 1A of the fuel section 1 includes a nuclear fuel 1Ab and a covering section 1Ac. The nuclear fuel 1Ab can be formed, for example, by baking uranium powder into a plate shape (disk shape). The covering portion 1Ac is provided to cover the entire surface of the nuclear fuel 1Ab. The covering part 1Ac is made of a metal or a carbon compound, and is held so as to suppress the release of fission products (FP) released by nuclear fission of the nuclear fuel 1Ab.

As described above, the nuclear reactor 11 of the first embodiment is configured to include the fuel section 1 in which the coating section 1Ac is provided on the surface of the nuclear fuel 1Ab, and the heat conduction section 3 described above. Therefore, the nuclear reactor 11 of the first embodiment can efficiently extract heat from the nuclear fuel 1Ab of the fuel section 1, which is the reactor core, by the heat conduction section 3 while retaining the fission products.

Specifically, in the nuclear reactor 11 of the first embodiment, the fuel section 1 constitutes a fuel layer 1A in which a coating section 1Ac is provided on the surface of a nuclear fuel 1Ab formed in a plate shape. The heat conductive part 3 constitutes a heat conductive layer 3A formed in a plate shape, and is provided in a laminated manner facing the covering part 1Ac of the fuel layer 1A. That is, the fuel part 1 and the heat conductive part 3 are provided with a heat conductive layer 3A stacked on each other facing the covering part 1Ac of the fuel layer 1A, and a heat conducting part 3 and the heat conducting part 3 facing the covering part 1Ac. The fuel portion 1 is provided in a stacked manner. Therefore, the nuclear reactor 11 of the first embodiment can efficiently extract heat from the nuclear fuel 1Ab of the fuel section 1 due to the laminated structure of the fuel layer 1A and the heat conductive layer 3A, both of which are formed in a plate shape. In addition, the nuclear reactor 11 of the first embodiment has a fuel layer 1A in which a covering part 1Ac is provided on the surface of the nuclear fuel 1Ab formed in a plate shape, thereby providing a covering part on the surface of a large number of pellet-shaped nuclear fuels. Compared to the case where the covering portion 1Ac is provided, the surface area on which the covering portion 1Ac is provided can be reduced, and the fuel filling rate can be improved. In addition, in the fuel layer 1A in which the covering part 1Ac is provided on the surface of the nuclear fuel 1Ab formed in a plate shape, when the control mechanism 4 is a control rod 4B, the covering part 1Ac is also provided on the inner surface of the hole penetrating the control rod 4B. provided.

Moreover, specifically, in the nuclear reactor 11 of Embodiment 1, as shown in FIGS. 10 to 12, in the fuel section 1, the nuclear fuel 1Ab forming the fuel layer 1A is configured as a plurality of block-shaped nuclear fuel members 1B. As shown in FIG. 9, a covering portion 1Ac is provided on the surface of each nuclear fuel member 1B assembled into a plate shape. FIG. 10 shows an example in which block-shaped nuclear fuel members 1B are formed into rectangular shapes and arranged so that their ends can touch each other. FIG. 11 shows an example in which block-shaped nuclear fuel members 1B are formed in a triangular shape and arranged so that their ends can touch each other. FIG. 12 shows an example in which block-shaped nuclear fuel members 1B are formed in a hexagonal shape and arranged so that their ends can touch each other. In this manner, in the embodiments shown in FIGS. 10 to 12, each flat block-shaped nuclear fuel member 1B is arranged in a plate shape to constitute a nuclear fuel 1Ab. Therefore, in the nuclear reactor 11 of the first embodiment, a nuclear fuel 1Ab is configured by a plurality of block-shaped nuclear fuel members 1B, and by collectively providing a covering part 1Ac, the reactor 11 can be configured as shown in FIGS. 2 to 5 and 9. The plate-shaped fuel section 1 can be easily manufactured.

Specifically, in the nuclear reactor 11 of Embodiment 1, as shown in FIG. 13, the fuel part 1 includes a nuclear fuel member 1C in which a coating part 1Ac is provided on the surface of nuclear fuel 1Ab formed in the form of particles. are doing. As shown in FIG. 14, the nuclear fuel member 1C is composed of a plurality of heat conductive parts 3' as a base material. For example, titanium, nickel, copper, or graphite can be used for the heat conductive part 3'. In particular, graphene can be used as graphite. It is preferable that the nuclear fuel member 1C has a diameter of, for example, 1 mm, and the covering portion 1Ac is made of, for example, ceramics. Therefore, in the nuclear reactor 11 of the first embodiment, by configuring the fuel part 1 in which a plurality of nuclear fuel members 1C are assembled using the heat conduction part 3' as a base material, the heat conduction part 3 is able to hold the nuclear fission products while the reactor core Heat can be efficiently extracted from the nuclear fuel 1Ab of the fuel section 1. Moreover, the nuclear reactor 11 of Embodiment 1 can be formed as a plate-shaped fuel layer 1A as shown in FIGS. 2 to 5 in the fuel section 1 shown in FIG. 14. Furthermore, in the nuclear reactor 11 of the first embodiment, the fuel part 1 shown in FIG. 14 is formed by using a block-shaped nuclear fuel member 1B as shown in FIGS. 10 to 12, and omitting the coating part 1Ac on the surface thereof. I can do it. Moreover, the nuclear reactor 11 of Embodiment 1 can be formed as a plate-shaped fuel layer 1A as shown in FIG. 2 in the fuel part 1 shown in FIG. 3A) are provided in a stacked manner. That is, the fuel part 1, which is made up of a plurality of nuclear fuel members 1C using the heat conductive part 3' as a base material, and the heat conductive part (thermal conductive part 3 (thermal conductive layer 3A)) different from the heat conductive part 3' are mutually It is formed into a plate shape and is provided in a laminated manner. Thereby, it is possible to significantly obtain the effect of efficiently extracting heat from the nuclear fuel 1Ab of the fuel section 1, which is the reactor core. In addition, the nuclear reactor 11 of Embodiment 1 is formed as a plate-shaped fuel layer in the fuel part 1 shown in FIG. A structure in which a plurality of layers are stacked may be used.

Moreover, specifically, in the nuclear reactor 11 of Embodiment 1, the heat conduction part 3 (heat conduction layer 3A) transmits the heat of the fuel part 1 to the outside by solid heat conduction. Therefore, the nuclear reactor 11 of Embodiment 1 can extract heat while suppressing leakage of radiation, and can ensure a high output temperature.

Further, in the configuration of the nuclear reactor 11 of the first embodiment, when the arrangement density of the nuclear fuels 1Ab is made uniform, the temperature of the central portion of the fuel section 1 is higher than that of the outer peripheral portion. The nuclear reactor 11 of Embodiment 1 is configured to extract heat toward the outer peripheral side in the radial direction of the fuel section 1, and in order to facilitate the extraction of heat, it is preferable to equalize the temperature distribution of the nuclear fuel 1Ab. Therefore, in the nuclear reactor 11 of Embodiment 1, the arrangement density of the nuclear fuel 1Ab in the fuel part 1 is made lower in the central part than in the outer peripheral part, thereby making the temperature distribution of the fuel part 1 uniform and making it easier to extract heat. can do.

[Embodiment 2]
FIG. 15 is a schematic diagram showing a nuclear reactor according to the second embodiment. FIG. 16 is a schematic cross-sectional view of a nuclear reactor according to Embodiment 2. FIG. 17 is a schematic diagram showing another form of the nuclear reactor according to the second embodiment. FIG. 18 is an enlarged schematic diagram of the heat conduction section of the nuclear reactor according to the second embodiment. FIG. 19 is a schematic diagram showing another form of the nuclear reactor according to the second embodiment. FIG. 20 is an explanatory diagram of the form shown in FIG. 18.

As shown in FIGS. 15 and 16, the nuclear reactor 12 includes a fuel section (core) 101, a shield section 102, and a heat conduction section 103. Although not explicitly shown in the drawings, the nuclear reactor 12 also includes the control mechanism 4 described in the first embodiment.

The fuel portion 101 is formed into a columnar shape as a whole. In the second embodiment, the fuel portion 101 is formed into a substantially cylindrical shape. The direction in which this columnar shape extends is sometimes referred to as the axial direction. Further, the direction perpendicular to the axial direction is sometimes referred to as the radial direction. The fuel portion 101 contains uranium, which is nuclear fuel.

The shielding part 102 covers the periphery of the fuel part 101. The shielding part 102 is made of a metal block and prevents radiation from leaking to the outside of the fuel part 101 by reflecting radiation (neutrons) irradiated from the nuclear fuel. The shield 102 may be referred to as a reflector depending on the neutron scattering and neutron absorption capabilities of the material used.

In the second embodiment, the shielding part 102 includes a body 102A formed in a cylindrical shape so as to surround the entire outer periphery of the columnar shape of the fuel part 101, and lid bodies 102B that close both ends of the body 102A. In addition, when the shielding part 102 accommodates the fuel part 101 therein, it is preferable to fill the inside of the shielding part 102 with an inert gas such as nitriding gas in order to prevent oxidation of the inside.

The heat conduction portion 103 is formed into a rod shape extending in the axial direction. The heat conduction part 103 penetrates the shielding part 102 and is inserted into the inside of the fuel part 101 covered by the shielding part 102, so that it extends to the inside of the fuel part 101 and the outside of the shielding part 102. . The heat conduction section 103 transmits heat generated by the fission reaction of the nuclear fuel in the fuel section 101 to the outside of the shielding section 102 by solid heat conduction. For example, titanium, nickel, copper, or graphite can be used for the heat conduction part 103. In particular, graphene can be used as graphite. A portion of the heat conduction portion 103 extending outside the shielding portion 102 is provided to be able to exchange heat with the refrigerant inside the reactor vessel 51.

The control mechanism 4 can be configured as the control drum 4A shown in FIG. 3 described in the first embodiment. The control drum 4A is arranged in the shielding part 102. The detailed configuration of the control drum 4A is the same as described in the first embodiment, and the explanation will be omitted here. Further, the control mechanism 4 can be configured as the control rod 4B shown in FIG. 4 described in the first embodiment. The control rod 4B is arranged in the fuel section 1 so as to extend in the axial direction parallel to the heat conduction section 103. The detailed configuration of the control rod 4B has been explained in the first embodiment, and the explanation will be omitted here.

Therefore, in the nuclear reactor 12 of the second embodiment, the heat generated by the fission reaction of the nuclear fuel in the fuel section 101 can be extracted to the outside of the shielding section 2 by solid heat conduction using the heat conduction section 103. The heat extracted to the outside of the shielding part 102 is transferred to the refrigerant, causing the turbine 55 to rotate.

In the nuclear reactor 12 of the second embodiment, the heat of the nuclear fuel in the fuel section 101 can be extracted to the outside of the shielding section 102 by solid heat conduction through the heat conduction section 103 (see arrow in FIG. 15), and the heat can be transferred to the refrigerant. As a result, the nuclear reactor 12 of the second embodiment can prevent leakage of radioactive substances and the like. In addition, in the nuclear reactor 12 of the second embodiment, the heat conduction section 103 is arranged to extend inside the fuel section 101 and outside the shielding section 102, so that the heat transfer distance of the nuclear fuel in the fuel section 101 is suppressed. It can be taken out of the shielding part 102 at the same time. As a result, the nuclear reactor 12 of the second embodiment can ensure a high output temperature. Although the nuclear reactor 12 of Embodiment 2 has been described as having a heat conduction section 103 that takes out heat by solid heat conduction, for example, another heat conduction section may be a fluid heat conduction section using a heat pipe filled with fluid. It is also possible to use a form that extracts heat.

Further, in the nuclear reactor 12 of the second embodiment, as shown in FIG. 17, the heat conduction part 103 is arranged to penetrate the fuel part 101 and extend to the outside on the opposite side of the shielding part 102 in the axial direction. It's okay. That is, in the nuclear reactor 12 shown in FIG. 17, the heat conduction part 103 extends in the axial direction through both lids 102B of the shielding part 102, and is arranged at each outside on the opposite side of the shielding part 102. Therefore, the nuclear reactor 12 of the second embodiment can take out the heat of the fuel section 101 to the outside on the opposite side of the shielding section 102 by solid heat conduction (see arrows in FIG. 17).

Further, in the nuclear reactor 12 of the second embodiment, as shown in FIG. 18, the heat conduction part 103 is preferably formed into a bar shape by stacking continuous plate members 103D in the extending direction of the bar shape. For example, graphene can be used for the heat conduction part 103. Graphene has a structure in which a hexagonal lattice made of carbon atoms and their bonds is continuous, and has high heat conductivity in the continuous direction of the hexagonal lattice. . By using this graphene as the sheet-like plate material 103D, the hexagonal lattice is continuous along the surface of the plate material 103D. Then, the plate materials 103D are stacked to form a bar shape. Then, the thermally conductive portion 103 has high heat transferability in the axial direction, which is the direction in which the rod shape extends along the surface of the plate material 103D. Therefore, the thermally conductive portion 103 has high heat transferability with respect to the portion extending in the axial direction to the outside of the shielding portion 102. As a result, the nuclear reactor 12 of the second embodiment can improve the efficiency of transmitting the heat extracted by the heat conduction section 103 to the refrigerant.

Furthermore, as shown in FIGS. 19 and 20, the nuclear reactor 12 of the second embodiment may include another heat conduction section 104 attached to the outside of the shielding section 102 from which the heat conduction section 103 is not extended. In the second embodiment, the shielding part 102 from which the heat conductive part 103 is not extended is the body 102A, and another heat conductive part 104 is attached to the outside of the body 102A. As shown in FIGS. 19 and 20, another heat conduction section 104 is formed in a ring shape surrounding the body 102A of the shielding section 102, and is attached in plural in the axial direction. Further, although not clearly shown in the drawings, a plurality of other heat conductive sections 104 may be formed in a plate shape extending in the axial direction, and may be attached in plural so as to surround the body 102A of the shielding section 102. For example, titanium, nickel, copper, or graphite can be used for the other heat conductive part 104. In particular, graphene can be used as graphite. By providing another heat conduction part 104, heat can also be extracted from the outside of the shielding part 102 from which the heat conduction part 103 is not extended (see arrow in FIG. 19). As described with reference to FIGS. 6 and 7 in the first embodiment, the heat taken out by this other heat conduction section 104 is exchanged with the refrigerant by first passing the refrigerant outward in the radial direction. After that, the refrigerant is returned and passed radially inward, and then the refrigerant is delivered to the heat exchanger 52 .

In addition, in the nuclear reactor 12 of the second embodiment, the heat conduction part 103 is formed into a rod shape by overlapping the plate materials 103D that are continuous in the extending direction of the rod shape. , it is preferable that the heat conducting part 104 be disposed toward another heat conducting part 104 attached to the outside of the shielding part 102. As shown in FIG. 18, the heat conduction part 103 is formed into a rod shape by overlapping the surfaces of the plate material 103D that are continuous in the extending direction of the rod shape. facing in the opposite direction. Then, the end 103Da of the plate material 103D forming the rod-shaped peripheral surface is arranged toward another heat conductive part 104 attached to the outside of the shielding part 102, as shown by the arrow in FIG. As described above, the thermally conductive portion 103 has high heat transferability along the surface of the plate material 103D. Therefore, by directing the end 103Da facing in the opposite direction along the surface of the plate material 103D toward another heat conduction section 104, the heat transferability to the other heat conduction section 104 is increased. As a result, in the nuclear reactor 12 of the second embodiment, the heat extracted by the heat conduction section 103 can be efficiently extracted by another heat conduction section 104, so that the efficiency of transferring the heat to the refrigerant can be increased.

In the nuclear reactor 12 of the second embodiment, the fuel part 101 includes nuclear fuel and a covering part, like the fuel part 1 of the first embodiment, although not clearly shown in the drawings. Nuclear fuel can be formed, for example, by burning uranium powder into a columnar shape. The covering portion is provided to cover the entire surface of the nuclear fuel. The covering portion is made of a metal or a carbon compound, and is intended to hold so as to suppress the release of fission products (FP) released by nuclear fission of nuclear fuel.

In this way, the nuclear reactor 12 of the second embodiment is configured to include the fuel section 101 in which the surface of the nuclear fuel is provided with a coating section, and the above-mentioned heat conduction section 103. Therefore, the nuclear reactor 12 of the second embodiment can efficiently extract heat from the nuclear fuel in the fuel section 1, which is the reactor core, by the heat conduction section 103 while retaining the fission products. In addition, the nuclear reactor 12 of the second embodiment has a fuel section 1 in which a coating is provided on the surface of a nuclear fuel formed in a columnar shape, so that the coating can be provided on the surface of a large number of pellet-shaped nuclear fuel. In comparison, the surface area on which the covering portion is provided can be reduced, and the fuel filling rate can be improved. In addition, in the fuel part 1 in which a coating is provided on the surface of the nuclear fuel formed in a columnar shape, when the control mechanism 4 is a control rod 4B, a coating is also provided on the inner surface of a hole passing through the control rod 4B.

Further, in the nuclear reactor 12 of the second embodiment, although not shown in the drawings, the nuclear fuel is configured as a plurality of block-shaped nuclear fuel members in the fuel part 101, similar to the fuel part 1 of the first embodiment, and each nuclear fuel A covering portion may be provided on the surface of the members gathered together in a columnar shape. Therefore, in the nuclear reactor 12 of the second embodiment, the nuclear fuel is composed of a plurality of block-shaped nuclear fuel members, and by collectively providing the covering portion, it is possible to easily manufacture a single columnar fuel portion 101.

In addition, in the nuclear reactor 12 of the second embodiment, the fuel part 101 has a coating part provided on the surface of the nuclear fuel formed in the form of particles, similar to the fuel part 1 of the first embodiment, although it is not shown in the drawings. It may have a nuclear fuel member, and this nuclear fuel member may be composed of a plurality of heat conductive parts as a base material. Therefore, in the nuclear reactor 12 of Embodiment 2, by configuring the fuel part 101 in which a plurality of nuclear fuel members are assembled using a heat conductive part as a base material, the fuel part which is a reactor core is held by the heat conductive part while retaining nuclear fission products. Heat can be extracted efficiently from 101 nuclear fuel. Further, in the nuclear reactor 12 of the second embodiment, in the fuel part 101 in which a plurality of nuclear fuel members are collected using a heat conductive part as a base material, the nuclear fuel member can be formed in the form of a block, and the covering part on the surface thereof may be omitted. . In addition, the nuclear reactor 12 of the second embodiment has a structure in which the above-described heat conductive part 103 formed in a rod shape is provided in the fuel part 101 in which a plurality of nuclear fuel members are gathered together using a heat conductive part as a base material. The effect of efficiently extracting heat from the nuclear fuel of the fuel section 101 can be significantly obtained.

Furthermore, in the nuclear reactor 12 of the second embodiment, the heat conduction section 103 transmits the heat of the fuel section 101 to the outside by solid heat conduction. Therefore, the nuclear reactor 12 of the second embodiment can extract heat while suppressing radiation leakage by transmitting the heat of the fuel part 101 to the outside through solid heat conduction, and can ensure a high output temperature.

In addition, in the nuclear reactor 12 of the second embodiment, as described above, the heat conduction part 103 is formed in a rod shape, extends in the axial direction in the fuel part 101, and is arranged to penetrate the lid 102B of the shielding part 102. ing. In this configuration, when the arrangement density of the fuel portions 101 is made uniform, the temperature of the heat taken out is higher in the central portion than in the outer peripheral portion. Therefore, when exchanging heat with the refrigerant in the heat conduction section 103, the refrigerant is first passed through the radially outer portion of the heat conduction section 103, and then passed through the radially inner portion of the heat conduction section 103. After that, the refrigerant is sent to the heat exchanger 52. In this way, the efficiency of transmitting the heat extracted by the heat conduction section 103 to the refrigerant can be increased. Furthermore, when the arrangement density of the fuel part 101 is made uniform, the temperature in the central part becomes higher than that in the outer peripheral part, but the area in the central part is small and the efficiency of extracting heat decreases. In order to increase the density, the rod-shaped heat conductive portions 103 may be made thicker in the central portion of the fuel portion 101 or arranged closer together. Further, by increasing the arrangement density of the fuel portion 101 in the outer peripheral portion of the fuel portion 101 having a large area, it is possible to increase the efficiency of extracting heat in the portion having a large area. In this case, the rod-shaped heat conductive parts 103 may be made thicker in the outer peripheral part of the fuel part 101 or arranged closer together so that the density of the heat conductive parts 103 is higher in the outer peripheral part of the fuel part 101. .

[Embodiment 3]
FIG. 21 is a schematic diagram showing a nuclear reactor according to Embodiment 3.

The nuclear reactor 13 of the third embodiment combines the configuration of the nuclear reactor 11 of the first embodiment and the configuration of the nuclear reactor 12 of the second embodiment described above. Therefore, the same components as those of the nuclear reactor 11 and the nuclear reactor 12 are designated by the same reference numerals, and the description thereof will be omitted.

The nuclear reactor 13 of the third embodiment includes the fuel section 1, the shielding section 2, the heat conduction section (first heat conduction section) 3 of the nuclear reactor 11 of the first embodiment, and the heat conduction of the nuclear reactor 12 of the second embodiment. (second heat conduction part) 103. Although not explicitly shown in the drawings, the nuclear reactor 13 also includes the control mechanism 4 (control drum 4A, control rod 4B) described in the first embodiment.

That is, in the nuclear reactor 13, a hole is formed in the fuel layer 1A of the fuel part 1 and the heat conductive layer 3A of the heat conductive part 3, into which the heat conductive part 103 is inserted.

In the nuclear reactor 13 of Embodiment 3, the heat conduction parts include a first heat conduction part 3 which is formed in a plate shape and is arranged in a stacked manner with the fuel layer 1A, and a first heat conduction part 3 which is formed in a rod shape and is stacked on the fuel layer 1A and the first heat conduction part 3. A second heat conductive part 103 is arranged extending in the axial direction overlapping with the conductive part 3. Therefore, in the nuclear reactor 13 of Embodiment 3, the first heat conduction part 3 and the second heat conduction part 103 are disposed so as to penetrate the shield part 2 and extend to the inside of the fuel part 1 and the outside of the shield part 2. The heat of the fuel part 1 can be taken out to the outside of the shielding part 2 by solid heat conduction.

The reactor 13 of the third embodiment has the same configuration as the reactor 11 of the first embodiment and the reactor 12 of the second embodiment described above, so that the same effects as those of the first and second embodiments can be obtained.

1 Fuel part 1A Fuel layer 1Aa Outer peripheral surface 1Ab Nuclear fuel 1Ac Coating part 1B Nuclear fuel member 1C Nuclear fuel member 2 Shielding part 2A Shielding layer 2Aa Through hole 2B Lid part 3 Heat conduction part (first heat conduction part)
3A Heat conductive layer 3B Notch 3C Heat transfer tube 3Ca Inner heat transfer tube 3Cb Outer heat transfer tube 3D Plate material 4 Control mechanism 4A Control drum 4Aa Neutron absorber 4B Control rod 11, 12, 13 Reactor 50 Nuclear power generation system 51 Reactor vessel 52 Heat Exchanger 53 Heat conduction section 54 Refrigerant circulation means 55 Turbine 56 Generator 57 Cooler 58 Compressor 101 Fuel section 102 Shielding section 102A Body 102B Lid body 103 Heat conduction section (second heat conduction section)
103D Plate material 103Da End 104 Heat conduction part

Claims (5)

Comprising a fuel part in which a coating part is provided on the surface of nuclear fuel, and a heat conduction part ,
A nuclear reactor, wherein the heat conduction part and the fuel part are stacked and provided facing the covering part, and the heat conduction part is provided so as to protrude from an outer periphery of the fuel part . 2. The nuclear reactor according to claim 1 , wherein the nuclear fuel in the fuel part is composed of a plurality of block-shaped nuclear fuel members, and the coating part is provided on a surface of the block-shaped nuclear fuel members. It has a nuclear fuel member in which a coating part is provided on the surface of nuclear fuel formed in the form of particles, and the nuclear fuel member has a fuel part that is composed of a plurality of heat conductive parts as a base material,
A nuclear reactor, wherein the fuel part and another heat conduction part are formed into plate shapes and are stacked on top of each other. It has a nuclear fuel member in which a coating part is provided on the surface of nuclear fuel formed in the form of particles, and the nuclear fuel member has a fuel part that is composed of a plurality of heat conductive parts as a base material,
A nuclear reactor, wherein the fuel part and another heat conduction part are formed into plate shapes and are stacked on top of each other , and the another heat conduction part is provided to protrude from an outer periphery of the fuel part . The nuclear reactor according to any one of claims 1 to 4 , wherein the heat conduction section transmits the heat of the fuel section to the outside by solid heat conduction.

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